The dynamics of the VSC can be modelled by both state-space and impedance-based modelling approaches [1]}, [2]}. The small-signal model for stability studies at the point of common coupling (PCC), as displayed in Fig. REF , can be formulated to state-space equations as
\(\dot{x}(t) & =\mathbf {A}x(t)+\mathbf {B}u(t) & u(t)=\Delta v_{qd}(t)\\y(t) & =\mathbf {C}x(t)+\mathbf {D}u(t) & y(t)=\Delta i_{c-qd}(t),\) 
